When is the best time to collect my sample, and what can affect the results?

Updated on

Your microbiome changes over time, so your results provide a snapshot of the day you collect your sample. Always follow your kit instructions. If you want your sample to reflect your usual state, bear the following guidance in mind: 

  • Antibiotics. Wait at least three months after finishing treatment, unless you specifically want to see its effects. 

  • Probiotics and prebiotics. If you want to assess your microbiome without supplements, stop taking them a few days beforehand. If a healthcare professional recommended them, consult them first. If you take them daily and want to see your usual state, continue taking them. 

  • Diet. Maintain your usual eating habits during the preceding week, and avoid collecting your sample immediately after travelling, festive celebrations or a short-term extreme diet. 

  • Acute digestive problems. After a gut infection, food poisoning, acute diarrhoea or laxative use, wait until your bowel habits return to normal. 

  • Colonoscopy. Bowel preparation temporarily changes the microbiome: wait a few weeks until your usual bowel habits return. 

  • Bleeding. If you are menstruating or have bleeding haemorrhoids, wait until the bleeding stops. 

  • Regular medication. Do not stop any prescribed medication or recommended supplement to take the test without consulting your doctor first. Some medicines, such as omeprazole or metformin, alter the microbiome; this is normal and forms part of your snapshot. 

These timings are a guide: no waiting period guarantees a return to a 'baseline' microbiome for everyone.